In the early 2000s, coronavirus-infected bats jumped into raccoon dogs and other wild mammals in southwestern China. Some of these animals were being sold in markets where the coronavirus has sprang up again. As a result, the SARS Pandemic spread to 33 countries and killed 774 people. A few months later, scientists discovered a mammalian coronavirus known as Palmcoten, sold in a market at the heart of the outbreak.
In a study published Wednesday, a team of researchers compared the evolutionary narrative of SAR to the story of Covid 17 years later. Researchers analyzed the genomes of the two coronaviruses that caused the pandemic, along with 248 related coronaviruses in bats and other mammals.
Jonathan Pechal, an evolutionary virologist at the University of Edinburgh and author of the new study, said the two coronavirus histories followed a parallel pathway. “In my opinion, they are very similar,” he said.
In both cases, Dr. Pekal and his colleagues claim that the coronavirus jumped from bats in southwestern China to wild mammals. In a short time, wildlife traders took infected animals hundreds of miles to urban markets, and the virus wreaked havoc for humans.
“When you sell wildlife in urban centres, you'll often have a pandemic,” said Michael Warby, an evolutionary biologist at the University of Arizona and author of the new study.
This research lands at a political moment. Last month, the White House created a web page called “Laborek: The True Origins of Covid 19.” This claims that the pandemic was caused by an accident in the lab in Wuhan, China, rather than a ripple of the market.
In a budget proposal Friday, the White House explained that it was “confirming” the lab leak, justifying its $18 billion cut to the National Institutes of Health.
The Chinese government responded with a flat denial that Covid was caused by a leak in Wuhan Lab, increasing the likelihood that the virus had instead emerged from the US Biodefense lab.
“A thorough and detailed investigation into the origin of the virus should be conducted in the United States,” the statement read.
Sergei Pond, Virologist at Temple University, said he does not believe that Covid's origins have been resolved. However, he was worried that the jammed Cen language from two governments would make it difficult for scientists to investigate and discuss the origins of Covid.
“If it wasn't tragic, you'd have to laugh, that's what happened so far,” Dr. Pond said.
In the first weeks of Covid Pandemic in early 2020, they alleged that the responsible virus, SARS-Cov-2, is a biological weapon created by the Chinese military. A group of scientists who analyzed the data available at the time rejected the idea. They could not rule out accidental lab leaks, but they supported the natural origins of Covid.
Over time, Dr. Warby, who was not part of that group, was unhappy with the lack of evidence yet to select one theory over the other. He has signed an open letter with 17 other scientists seeking more investigation to determine which explanation is more likely.
“To us, it seemed like there was a lot we didn't know, so don't throw away the idea of ​​Labreek,” Dr. Warby said. “Let's study.”
When Dr. Warby and other scientists began studying the origins of Covid, the American Intelligence Agency also evaluated it. Their ratings are mixed. The FBI and CIA support escape from the Virology Institute in Wuhan, but with little certainty. The Ministry of Energy is leaning low confidence in the virus that will escape from another lab in Wuhan. Other institutions leaned towards natural origin.
Scientists are unable to assess the basis of conclusions, as the institution does not publish evidence or analysis. However, Dr. Warby and other researchers have published a series of papers in scientific journals. Along the way, Dr. Warby was convinced that the COVID pandemic had begun at the Hukai seafood market in Uhan.
“Scientifically, it's as clear as HIV and the Spanish flu,” Dr. Warby said, referring to two diseases that also studied his origins.
In the new study, Dr. Warby, Dr. Pekal and his colleagues compared 250 coronavirus genomes and used genetic similarities and differences to determine relationships. They were able to reconstruct the history of the coronavirus that causes both SARS and Covid – known as SARS-COV and SARS-COV-2.
The ancestors of both coronaviruses have been circulating in bats in China and most of their neighboring countries for hundreds of thousands of years. A directly ancestral bat that has lived in southwestern China and northern Laos over the past 50 years.
When the coronavirus infects bats, they sometimes ended up in the cells along with another coronavirus. When the cells created a new virus, they accidentally created a hybrid that carried genetic material from both the original coronavirus. This is known as recombination.
“These are not ancient events,” said David Rasmussen, a virologist at North Carolina State University who was not involved in the new research. “These things happen all the time. These viruses are really mosaic.”
In 2001, just a year before the SARS pandemic began in Guangzhou, researchers discovered that SARS-Cov had undergone the last genetic mix of bats. It was then possible that the final recombination had evolved the virus into a human pathogen. And as Guangzhou is hundreds of miles away from Sarskov's ancestral region, bats would not have been able to bring the virus to the city so little by little.
Instead, researchers generally agree. The ancestors of SARS-COV were infected with wild mammals that were later sold in markets around Guangzhou. A few months after the start of the SARS pandemic, researchers discovered SARS-COV in Palm citizens and other wild mammals sold in the market.
Researchers discovered a similar pattern when they turned to SARS-Cov-2, the cause of Covid. The final recombination of bats took place between 2012 and 2014, just five to seven years before the Covid pandemic, hundreds of miles before the northeastern part of Uhan.
It was also a major departure from the area where the virus's ancestors were circulating. But it rivaled the journey that Sarkov is a courtesy of the wildlife trade.
Supporters of the Labourek theory highlight the long distance between Uhan and where the closest relatives of SARS-Cov-2 were found. If bats flew to the area around Uhan and were unable to infect wild mammals there, they would have maintained and scientists must have been collecting coronaviruses from bats in southwestern China and tinkering with them in the lab.
American scientists have criticized the Uhan Virus Institute for its LAX protection measures in coronavirus experiments. However, no one provided evidence that the ancestors of SARS-COV-2 were at the Uhan Virology Institute before the pandemic. New research by Dr. Warby and his colleagues show that the bat coronavirus can travel long distances through the wildlife trade without the help of scientists.
Researchers argue that these findings agree with the study published in 2022, pointing to the Huannian Food Market in Uhan as the place where the community pandemic began. Wild mammals were sold there. Many early cases of Covid were recorded there, and Chinese researchers collected different strains of SARS-COV-2 that carry different mutations there. Dr. Warby and his colleagues claimed that the virus had spilled twice from wild mammals on the market.
Dr. Pond said the new study is consistent with the theory of wildlife spillover. However, he does not believe the problem has been resolved. He said last year that two statisticians were having problems with the models behind the 2022 study. Dr. Warby and his colleagues refuted the criticism. “That debate is still ongoing,” Dr. Pond said.
Mark Eloit, former director of the Pasteur Institute of Pasteur in Paris, said new research is important to give a clear grasp of where SARS-Cov-2 came from.
However, he also observed that the coronavirus differs significantly from the bat's most known relatives. After splitting from those viruses, it must have undergone mutation or recombination to adapt well to spread to humans.
“I argue that the possibility of recombination events, whether contingent or cautious, remains as plausible as the hypothesis of emergence via intermediate hosts in the market,” Dr. Eloit said.
Dr. Eloit and other scientists agreed that finding intermediate SARS-COV-2 in wild mammals would make a compelling argument against natural ripples. Chinese authorities saw several animals at the start of the pandemic and were unable to find the virus.
But before scientists could study, wildlife vendors at Huanan Market removed the animals from the food stalls. And when China stopped selling wildlife, farmers culled animals.
“There are big missing pieces and you can't really dance around it,” Dr. Pond said.
University of Utah geneticist Stephen Goldstein said that although he was not involved in the new study, the study served as a warning about the risks of the future coronavirus pandemic. Wild mammals sold in the market anywhere in the region where SARS and Covid have started can be a ride to cities hundreds of miles away. “These virus fragments are present in all of these places,” Dr. Goldstein said.
